This invention relates to an improved press switch and particularly a press switch that has a simple structure for reducing impedance.
The generally known press switch for channeling or output signal is widely used in various electrical devices such as mobile phone, computer and computer peripheral devices. FIG. 1 shows the general construction of a conventional press switch which includes a body 6, a first elastic element 7 and a second elastic element 8 located in the body 1, a terminal member 9 located in the body 6 above the first and second elastic elements 7 and 8, and a press element 10 located above the terminal member 9. When the press element 10 subjects to an external pressing force, the notch 101 at the press element 10 will press against an elastic strip 91 located on the terminal member 9. The elastic strip 91 in turn will press against the first and second elastic element 7 and 8 whereby to enable the first elastic element 7 bridging and linking the conductive element 61 and 62 for transmitting signals.
Applicant has disclosed an improved tact switch structure in U.S. Pat. No. 6,140,596 which includes a seat body, a first elastic element, a press set, and a closure body. After the first elastic element and the press set have been assembled and disposed in the seat body, the closure body is then combined on the seat body. When an external force is exerted on the press set, the press set will drive the first elastic element to contact and conductively joint with a first and a second electrode.
The examples of the prior art set forth above are capable of channeling and output electric signal. However they all have their share of disadvantages. For instance in the first example, the first and second elastic element 7 and 8 do not have anchoring positions in the body 6. Hence when the elastic strip 91 presses the first and second elastic element 7 and 8, displacement of the first and second elastic element 7 and 8 will occur, and might result in poor or no connection between the conductive elements 61 and 62. Some producers try to remedy this problem by fastening the conductive element 61 to the body 6, and pre-connect them electrically with the first elastic element 7. When the first and second elastic element 7 and 8 are being pressed, as long as the first elastic element 7 making contact with the conductive element 62, electrical connection will be established for transmitting signal. The second example also has similar problem as the first example does. Both of aforesaid examples also have fabrication difficulties and problems, and will result in higher production cost.
Furthermore, as the first example has relative complex structure, it needs more time and process to assemble, and thus has higher production cost. In addition, the conductive element 61 and 62, and the first and second elastic element 7 and 8, and terminal member 9 are all made of metal. They have more contact points during contact, and will result in higher impedance and consequently cause signal fading.
In view of aforesaid disadvantages, it is therefore an object of this invention to provide an improved press switch that has a simple structure and may be assembled with less process and time for reducing production cost.
Another object of this invention is to provide a structure that has smaller number of contact points whereby to greatly reduce impedance so that transmitting signals won""t be fading.
In order to achieve aforesaid objects, the press switch according to this invention includes a body, two terminal elements disposed in the body, a first elastic element located in the body, a press element located in the body above the first elastic element, and a face panel covering the body. When the press element subjects to an external pressing force, a second elastic element will be driven to press the first elastic element which in turn links the two terminals for output electric characteristics desired. When the press element is free from the external pressing force, the innate elastic force of the first and second elastic element will push the press element to its original position.